Eileen and her close friend (and former boyfriend) Robbie. He's a mustang and his name is actually Robin but whenever he uses that people are surprised when he's a guy, so he generally sticks with his nickname which is apparently more masculine.

Eileen and Robbie dated for a long time, but ended up parting ways because Eileen felt stuck (she wanted to get married, he felt they were close enough and didn't need paper to prove it; she was at a point in her life where little things became big deals and it didn't work out because neither felt that being unhappy all the time was a good thing).

They are closer in their friendship now that they're not together than they have been in a long time, and after Eileen's parting from Noah, Robbie lent a shoulder to cry on. Eileen is considering the idea of them being an "us" again, but nothing is certain. Sometimes life moves too fast and you have to slow down a moment and make sure you're headed the way you want to be headed.